A new anchor-siphon drainage combined method used for slope stabilization is proposed in this paper.It includes an anchoring section and a siphon drainage section.The novelty of the anchor-siphon drainage combined met...A new anchor-siphon drainage combined method used for slope stabilization is proposed in this paper.It includes an anchoring section and a siphon drainage section.The novelty of the anchor-siphon drainage combined method is the realization of the drainage and anchoring in the one inclined borehole.The engineering cost of drilling and the resulting disturbance to the slope is reduced.To validate the feasibility of the proposed method,a numerical method that combines the pore water pressure distribution after siphon drainage and the anchoring force of the anchoring section is used to evaluate the safety of the slope with the anchor-siphon drainage method.The proposed method was illustrated and validated with the Hongpu Village landslide,in Tonglu County,Zhejiang Province,in China.Compared with the common anchor bar with the same length in the anchoring section,the factor of safety(FOS)for Hongpu Village slope with anchorsiphon drainage is increased by 0.085.The calculation method of the optimal length ratio between the drainage section and the anchoring section and its influencing factors were studied.For the different design parameters,there is always an optimal length ratio of the drainage section.Compared with the siphon drainage and full-length anchor bar with the same borehole length,the anchor-siphon drainage combined method shows better landslide prevention ability.Moreover,when the optimized parameters with a bond strength of 560kPa,a borehole inclination of 35°,and no reduction in length are used,the calculated safety factor is 1.316,which is significantly higher than the FOS of 1.131 for the slope with siphon drainage.展开更多
Siphonic roof drainage systems (SRDS’s) have been widespread used now for approximately 40 years and are an efficient method of removing rainwater rapidly from roofs. SRDS’s are designed to run full-bore, resulting ...Siphonic roof drainage systems (SRDS’s) have been widespread used now for approximately 40 years and are an efficient method of removing rainwater rapidly from roofs. SRDS’s are designed to run full-bore, resulting in sub-atmospheric system pressures with high hydraulic driving heads and higher system flow velocities than conventionally guttered systems. Hence, SRDS’s normally require far fewer downpipes, and the depressurised conditions also mean that much of the collection pipework can be routed at a high level, thus reducing the extent of any underground pipework. But, they work properly at only one roof run-off rate and therefore suffer from sizing and operational problems including noise and vibration which limit their performance and adoption rate. Climate change is creating situations where normal ranges of rainfall intensity are being frequently exceeded, so the typical:storm ratios (rTS) are large increasing. Current SRDS’s typically operate within a small rTS range of 2. This may have an impact on the future uptake of SRDS’s. This paper describes the development of a novel SRDS which includes a small mobile cap at the roof of outlet appears to offer benefits and avoids sizing problems associated with current SRDS’s. The cap has the potential to avoid noise associated with making and breaking siphonic action through flow modulation. Laboratory scale tests demonstrate the basic feasibility of the cap system and indicate that the cap functions reliably. This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Basic on sizing and design optimiza-tion factors are suggested. The rTS range is increased from approximately 2 to approximately 6.展开更多
The siphon drainage is an effective measure for the slope groundwater control. However,for the traditional siphon drainage, limitations such as siphon lift restriction and poor reliability in longterm service prevent ...The siphon drainage is an effective measure for the slope groundwater control. However,for the traditional siphon drainage, limitations such as siphon lift restriction and poor reliability in longterm service prevent it from being widely used. In this study, an improved siphon drainage method with inclined borehole penetrating the deep part of the slope is proposed to overcome the limitations suffered by the traditional method. Through experimental research, theoretical analysis and engineering practice,the reliability and capability of the proposed method are investigated. The results demonstrate that with the inclined pipe the height difference between the control point of the groundwater level and the orifice can be controlled to be less than the height of the water column corresponding to the local atmospheric pressure. As a result, deep drainage can be achieved.In addition, by controlling the diameter of siphon drainage pipe not larger than 4 mm, a plug flow can be formed in the siphon pipe, which can prevent air accumulation in the siphon process and a continuous and effective siphon drainage is achieved. Through a practical project running smoothly since September 2013, it is found that the proposed method can effectively drain the groundwater deep in the slope and the maximum drawdown of groundwater level in boreholes can reach 8.5 m with an average drainage flow of 5.5 m3/d. The practical results also illustrate that 4 mm siphon pipe can be used to realize deep slope drainage and restart siphon automatically.展开更多
基金the financial support of the National Natural Science Foundation of China(Key Project)(No.42230702)National Natural Science Foundation of China(No.42277129)Natural Science Foundation of Zhejiang Province(No.LY21D020001)。
文摘A new anchor-siphon drainage combined method used for slope stabilization is proposed in this paper.It includes an anchoring section and a siphon drainage section.The novelty of the anchor-siphon drainage combined method is the realization of the drainage and anchoring in the one inclined borehole.The engineering cost of drilling and the resulting disturbance to the slope is reduced.To validate the feasibility of the proposed method,a numerical method that combines the pore water pressure distribution after siphon drainage and the anchoring force of the anchoring section is used to evaluate the safety of the slope with the anchor-siphon drainage method.The proposed method was illustrated and validated with the Hongpu Village landslide,in Tonglu County,Zhejiang Province,in China.Compared with the common anchor bar with the same length in the anchoring section,the factor of safety(FOS)for Hongpu Village slope with anchorsiphon drainage is increased by 0.085.The calculation method of the optimal length ratio between the drainage section and the anchoring section and its influencing factors were studied.For the different design parameters,there is always an optimal length ratio of the drainage section.Compared with the siphon drainage and full-length anchor bar with the same borehole length,the anchor-siphon drainage combined method shows better landslide prevention ability.Moreover,when the optimized parameters with a bond strength of 560kPa,a borehole inclination of 35°,and no reduction in length are used,the calculated safety factor is 1.316,which is significantly higher than the FOS of 1.131 for the slope with siphon drainage.
文摘Siphonic roof drainage systems (SRDS’s) have been widespread used now for approximately 40 years and are an efficient method of removing rainwater rapidly from roofs. SRDS’s are designed to run full-bore, resulting in sub-atmospheric system pressures with high hydraulic driving heads and higher system flow velocities than conventionally guttered systems. Hence, SRDS’s normally require far fewer downpipes, and the depressurised conditions also mean that much of the collection pipework can be routed at a high level, thus reducing the extent of any underground pipework. But, they work properly at only one roof run-off rate and therefore suffer from sizing and operational problems including noise and vibration which limit their performance and adoption rate. Climate change is creating situations where normal ranges of rainfall intensity are being frequently exceeded, so the typical:storm ratios (rTS) are large increasing. Current SRDS’s typically operate within a small rTS range of 2. This may have an impact on the future uptake of SRDS’s. This paper describes the development of a novel SRDS which includes a small mobile cap at the roof of outlet appears to offer benefits and avoids sizing problems associated with current SRDS’s. The cap has the potential to avoid noise associated with making and breaking siphonic action through flow modulation. Laboratory scale tests demonstrate the basic feasibility of the cap system and indicate that the cap functions reliably. This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Basic on sizing and design optimiza-tion factors are suggested. The rTS range is increased from approximately 2 to approximately 6.
基金financially supported by the National Key R&D Program of China (Grant No. 2018YFC1504704)the National Natural Science Foundation of China (Grant No. 41772276)Key R&D project of Zhejiang Province (Grant No. 2017C03006)
文摘The siphon drainage is an effective measure for the slope groundwater control. However,for the traditional siphon drainage, limitations such as siphon lift restriction and poor reliability in longterm service prevent it from being widely used. In this study, an improved siphon drainage method with inclined borehole penetrating the deep part of the slope is proposed to overcome the limitations suffered by the traditional method. Through experimental research, theoretical analysis and engineering practice,the reliability and capability of the proposed method are investigated. The results demonstrate that with the inclined pipe the height difference between the control point of the groundwater level and the orifice can be controlled to be less than the height of the water column corresponding to the local atmospheric pressure. As a result, deep drainage can be achieved.In addition, by controlling the diameter of siphon drainage pipe not larger than 4 mm, a plug flow can be formed in the siphon pipe, which can prevent air accumulation in the siphon process and a continuous and effective siphon drainage is achieved. Through a practical project running smoothly since September 2013, it is found that the proposed method can effectively drain the groundwater deep in the slope and the maximum drawdown of groundwater level in boreholes can reach 8.5 m with an average drainage flow of 5.5 m3/d. The practical results also illustrate that 4 mm siphon pipe can be used to realize deep slope drainage and restart siphon automatically.
